cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

time.h (2817B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/*
      3 * time.h - NTFS time conversion functions.  Part of the Linux-NTFS project.
      4 *
      5 * Copyright (c) 2001-2005 Anton Altaparmakov
      6 */
      7
      8#ifndef _LINUX_NTFS_TIME_H
      9#define _LINUX_NTFS_TIME_H
     10
     11#include <linux/time.h>		/* For current_kernel_time(). */
     12#include <asm/div64.h>		/* For do_div(). */
     13
     14#include "endian.h"
     15
     16#define NTFS_TIME_OFFSET ((s64)(369 * 365 + 89) * 24 * 3600 * 10000000)
     17
     18/**
     19 * utc2ntfs - convert Linux UTC time to NTFS time
     20 * @ts:		Linux UTC time to convert to NTFS time
     21 *
     22 * Convert the Linux UTC time @ts to its corresponding NTFS time and return
     23 * that in little endian format.
     24 *
     25 * Linux stores time in a struct timespec64 consisting of a time64_t tv_sec
     26 * and a long tv_nsec where tv_sec is the number of 1-second intervals since
     27 * 1st January 1970, 00:00:00 UTC and tv_nsec is the number of 1-nano-second
     28 * intervals since the value of tv_sec.
     29 *
     30 * NTFS uses Microsoft's standard time format which is stored in a s64 and is
     31 * measured as the number of 100-nano-second intervals since 1st January 1601,
     32 * 00:00:00 UTC.
     33 */
     34static inline sle64 utc2ntfs(const struct timespec64 ts)
     35{
     36	/*
     37	 * Convert the seconds to 100ns intervals, add the nano-seconds
     38	 * converted to 100ns intervals, and then add the NTFS time offset.
     39	 */
     40	return cpu_to_sle64((s64)ts.tv_sec * 10000000 + ts.tv_nsec / 100 +
     41			NTFS_TIME_OFFSET);
     42}
     43
     44/**
     45 * get_current_ntfs_time - get the current time in little endian NTFS format
     46 *
     47 * Get the current time from the Linux kernel, convert it to its corresponding
     48 * NTFS time and return that in little endian format.
     49 */
     50static inline sle64 get_current_ntfs_time(void)
     51{
     52	struct timespec64 ts;
     53
     54	ktime_get_coarse_real_ts64(&ts);
     55	return utc2ntfs(ts);
     56}
     57
     58/**
     59 * ntfs2utc - convert NTFS time to Linux time
     60 * @time:	NTFS time (little endian) to convert to Linux UTC
     61 *
     62 * Convert the little endian NTFS time @time to its corresponding Linux UTC
     63 * time and return that in cpu format.
     64 *
     65 * Linux stores time in a struct timespec64 consisting of a time64_t tv_sec
     66 * and a long tv_nsec where tv_sec is the number of 1-second intervals since
     67 * 1st January 1970, 00:00:00 UTC and tv_nsec is the number of 1-nano-second
     68 * intervals since the value of tv_sec.
     69 *
     70 * NTFS uses Microsoft's standard time format which is stored in a s64 and is
     71 * measured as the number of 100 nano-second intervals since 1st January 1601,
     72 * 00:00:00 UTC.
     73 */
     74static inline struct timespec64 ntfs2utc(const sle64 time)
     75{
     76	struct timespec64 ts;
     77
     78	/* Subtract the NTFS time offset. */
     79	u64 t = (u64)(sle64_to_cpu(time) - NTFS_TIME_OFFSET);
     80	/*
     81	 * Convert the time to 1-second intervals and the remainder to
     82	 * 1-nano-second intervals.
     83	 */
     84	ts.tv_nsec = do_div(t, 10000000) * 100;
     85	ts.tv_sec = t;
     86	return ts;
     87}
     88
     89#endif /* _LINUX_NTFS_TIME_H */